Way OT - Combi Boiler Pressure

Hello! Hopefully someone can confirm that I know what I'm doing - ha ha :)
I've just topped up the boiler - initially the needle didn't move and then before I knew it the needle way over way too far and now presumably I need to lose pressure.
Presumably if I bleed a handy radiator that will do the trick? (when I can figure out how to bleed a radiator)
Not a clue what I'm doing really but learning as I go!
Thanks in advance folks - I'm getting a tad nippy here and think I'll need to put some heating on eventually!
Alison

Depending on the system there should be an vent in case the system over pressurises, usually a 15mm pipe going through wall, between the wall and boiler there's a normally a valve with a red knob/button, pull or press the knob/button and it should vent through the wall.

Depending on the system there should be an vent in case the system over pressurises, usually a 15mm pipe going through wall, between the wall and boiler there's a normally a valve with a red knob/button, pull or press the knob/button and it should vent through the wall.